Guarded winding drum



Dec. 13, 1955 s, MQSER 2,726,755

GUARDED WINDING DRUM Filed Nov; 23, 1953 To Load Man pulls this endINVENTOR. Irving 5. Maser,

A TOR/V5 Y- United States Patent O 2,726,755 GUARDED WINDING DRUM IrvingS. Moser, Houston, Tex., assignor, by mesne assignments, to EssoResearch and Engineering Company, Elizabeth, N. J., a corporation ofDelaware Application November 23, 1953, Serial No. 393,641 3 Claims.(Cl. 203-340) This application is directed to a guarded hoisting drum.

The objects and advantages of the present invention may be seen from thefollowing description taken with the drawing in which the single figureis in the form of an elevation with parts cut away and with portionsshown schematically.

It is conventional in the art to use a hoisting drum with a loadcarrying line wrapped around the hoisting drum with one end of the lineattached to the load and the other end held by an operator. The operatormay tighten the wraps of line on the hoisting drum so that the load islifted by frictional contact between the Wraps of the line and therotating hoisting drum. The operator may disengage the load from thehoisting drum by slackening the line so that there is not suflicientfrictional contact between the wraps of line and the drum to support theload.

The present invention is directed to a hoisting drum with which a loadsupporting line is used. In the device of the present invention, thewraps of line on the hoisting drum are totally enclosed so that only theends of the line are exposed. In this way the hazard of an operatorbeing caught in the wraps of line on the drum'is eliminated.

Turning now specifically to the drawing, a shaft A is adapted to beconnected to and rotated by a suitable prime mover P, such as a steamengine or the like. In order to simplify the drawing, the prime moverhas been shown schematically.

Mounted on shaft A are two coaxial cylindrical hoisting drums B and C.Drums B and C have their outside surfaces 7 and 8 respectively ofidentical diameter and have adjacent ends 9 and 10 substantiallyabutting each other so that they define a common cylindrical surface andyet allow the two drums to have rotational movement independent of eachother.

Drum B is fixed to shaft A with its axis concentric therewith by capscrews 11 and 12.

Drum C is mounted for free rotation with respect to shaft A and drum B.In the drawing, this free rotation is provided by bearing assemblies 13and 14 which are arranged to carry drum C on shaft A. It will be seenthat with this arrangement drum C is arranged for free rotation or maybe described as a free wheeling drum with respect to drum B and shaft A.

A load carrying line D is shown with a portion thereof wrapped on thecommon cylindrical surface provided by drums B and C with the wrapsdesignated as 15, 16, 17, 13, and 19 and the two ends designated as 20and 21.

A cover E is made up as a unit which consists of a cylindrical portion22 terminating in inwardly extending annulus shaped ends 23 and 24.Adjacent end 23 is an opening 25 through which end 20 of line D extendsand adjacent end 24 is an opening 26 through which end 21 of line Dpasses. The annular space bounded by the inner surface of cylindricalsection 22, the inner walls of ends 23 and 24 and the common cylindricalsurface of drums B and C embraces the wraps of line through 19,inclusive, of line D. While this space provides ample clearance for thefree operation of line D, its limits are such that addi- 2 tional wrapsof line cannot be put on the common cylindrical surface defined by drumsB and C. This insures that a fixed number of wraps of line remain in thedesired relationship at all times.

A power means F is arranged for moving cover E along the longitudinalaxis of shaft A and drums B and C. This power means is showndiagrammatically as a rectangle 27 which may represent, for example, apiston and cylinder assembly powered by compressed air, this assemblybeing connected through rod 28 to cover E. Means for actuating the powermeans is designated as G.

consists of a compressed air supply line 29 connected to a suitablesupply of compressed air, not shown in the drawing, and connected tovalve 30 which in turn is connected through compressed air line 31 tothe power means 27. The valve means 30 may be actuated by a treadle 32,the end of which may be engaged with the teeth of lever 33 pivoted atpoint 34. The treadle 32 may be released as desired by the use of footoperated lever 35 which is pivoted at point 36.

In the device shown, the maximum number of wraps of load carrying linewhich are intended to be used with the device are wrapped on the commoncylindrical surface defined by surfaces 7 and 8 of hoisting drums B andC. If the drum cover E is moved to its extreme right position, all ofthe wraps of line are on the surface 8 of free wheeling drum C and noload can be picked up by the drum shaft A. To carry a load, the cover Eis moved from its extreme right position to the left so as to cause thedesired number of wraps of line to be brought into contact with surface7 of drum B for carrying the load when the line D is frictionallyengaged therewith. For convenience it will be assumed that end 21 isfastened to the load while end 20 is handled by the operator and to liftthe load the operator pulls on end 20 with enough force toproduce therequired frictional contact between drum B and load carrying line D.

The wraps of line 15 to 19 are contained in cage E and these wraps aremoved longitudinally by moving cage E. In the embodiment shown, thismovement is actuated by prime mover F which in turn is controlled by theoperators actuation of treadle 32 and lever 35.

The preferred method for using the device of the present invention isfor the operator to move cage E to the extreme right position whencarrying no load. Then to pick up a load, the operator depresses treadle31 which forces the cage E to move to the left, the operator moving cageE to the left such an amount as to slide the desired number of turns ofline from free wheeling drum C to load carrying drum B.

It is Well known that the advantage of a hoisting drum may be designatedby the formula:

Tz=pull of operator =coefficient of friction 0=radians of contact ofrope on cathead Thus, the operator will cause cage E to place such anumber of turns on the load carrying drum B as is necessary and stillallow the operator to have a good feel on the line. Thus, although thenumber of turns carried in cage E is the number required to lift themaximum load to be handled by the device any time, the operator canselect the number of turns which will actually carry the load and stillallow him to have a good feel on the line since the turns which remainon the free wheeling spool C do not take up any load.

The assembly G While a'specific embodiment of the present invention hasbeen described, it will be obvious to a workman skilled I mounted on arotatingtshaft comprising, in combination,

a first drum having a cylindrical surface arranged to be concentricallyfixed to said shaft for rotation therewith, a second drum having acylindrical surface of the same diameter as said first drum, bearingmeans carried by said second drum for mounting it on said shaftconcentric with said shaft and with said first drum for rotativemovement with respect to said first drum and shaft with an end of saidfirst drum and an end of said second drum substantially abutting so thatthe outer surfaces of said first and second drums define receiving wrapsof line, a'cover slidably mounted on the cylindrical surfaces of saidfirst and second drums and cooperatingrtherewithto form an annularshaped space of fixeddimensions movable longitudinally along the commonaxis of said drums and receiving a single layer of a predeterminednumber of wraps of a load carrying'line with the ends of the line freelyslidable, and means connected to said cover arranged to move said coveralong the longitudinal axis of said drums.

2. A guarded hoisting drum assembly adapted to be mounted on a rotatingshaft comprising, in combination, a first drum having a cylindricalsurface arranged to be concentrically fixed to said shaft for rotationtherewith, a second drum having a cylindrical surface of'the samediameter as said first drum, bearing means carried by said second drumfor mounting it concentrically on said shaft for free rotative movementwith respect to saidfirst drum and said shaft with an end of said firstdrum and an end of said second drum substantially abutting so that theouter surfaces of said first and second drums define a commoncylindrical surface for receiving wraps of a single layer of line, agenerally cylindrical cover having inwardly a common cylindrical surfacefor wraps on said common cylindrical surface, a cover having ,Which aline may pass,

cover being radially spaced away from the surfaces of extending end'flanges mounted onrsaid first and second drums with said end flangesmaking sliding contact with the cylindrical surfaces of said drum withan opening at each end of said cover adjacent said end flanges through.the cylindrical portion of said said drums to receive a'. single layerof a predetermined number of wraps of a load carrying line, and meansconnected to said cover arranged to move said cover along thelongitudinal axis of said shaft. 7 a

3. A guarded hoisting drum comprising, in combination, a drum shaft, afirst cylindrical drum concentrically fixed tov said shaft for rotationtherewith, a second drum having the same diameteras said first drum,bearings arranged to mount'said second drum on said shaft with adjacentends of said first and second drums substantially abutting so that thesurfaces of said first and second drums define a common cylindricalsurface for receiving a single layer of wrap of a load carrying linewith said second drum freely rotative with respect to said shaft andsaid first drum, a load carrying line having a single layer of acylindrical body and inwardly extending end flanges with a first openingat one end and a second opening at the other end through which a linemay pass mounted, over the wraps of said line with a first end of theline extending through the first opening and a second end of the lineextending through said second opening, the inner surface of said covercooperating with the common cylindrical surface of said first and seconddrums to define an annulus for receiving a single layer of apredetermined number of wraps of said line, and means arranged to movesaid cover along the longitudinal axis of said shaft and drums.

References Cited in the file of this patent UNITED STATES PATENTSSegelhorst Apr. 8, 1924 Kelley Sept. 12, 1950

